U.S. patent application number 11/910135 was filed with the patent office on 2008-11-06 for portable information terminal device and display terminal device.
This patent application is currently assigned to Sharp Kabushiki Kaisha. Invention is credited to Keiji Inoue, Akio Sakaguchi, Yasuyuki Taniguchi.
Application Number | 20080272995 11/910135 |
Document ID | / |
Family ID | 37073228 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080272995 |
Kind Code |
A1 |
Sakaguchi; Akio ; et
al. |
November 6, 2008 |
Portable Information Terminal Device And Display Terminal
Device
Abstract
[Summary] [Object] It is an object of the present invention to
provide a portable information terminal device and a display device
capable of effectively suppressing a display screen from being
peeped from an oblique direction. [Means for Settlement] A first
pattern area and a second pattern area are formed in a display area
of a display device 5; in a wide viewing field mode, the whole of
the display area is brought into a wide viewing angle state; and in
a narrow viewing field mode, a first divided state in which the
display area except the first pattern area is brought into a narrow
viewing angle state, and a second divided state in which the
display area except the second pattern area is brought into the
narrow viewing angle state are dynamically switched. For this
reason, if the display area in the narrow viewing field mode is
peeped from the oblique direction, a high contrast moving pattern
arising from the difference in viewing angle is viewed, and thereby
the conscious of the peeper can be attracted to the pattern.
Accordingly, even if a screen display is visible with a low
contrast, it can be prevented from being easily made out.
Inventors: |
Sakaguchi; Akio; (Hiroshima,
JP) ; Taniguchi; Yasuyuki; (Hiroshima, JP) ;
Inoue; Keiji; (Hiroshima, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Sharp Kabushiki Kaisha
Osaka
JP
|
Family ID: |
37073228 |
Appl. No.: |
11/910135 |
Filed: |
March 28, 2006 |
PCT Filed: |
March 28, 2006 |
PCT NO: |
PCT/JP2006/306263 |
371 Date: |
October 29, 2007 |
Current U.S.
Class: |
345/87 |
Current CPC
Class: |
G06F 1/1637 20130101;
G06F 1/1616 20130101; G09G 3/3648 20130101; G06F 1/1647 20130101;
G02F 1/13471 20130101; G02F 1/1323 20130101; G09G 3/2014
20130101 |
Class at
Publication: |
345/87 |
International
Class: |
G09G 3/36 20060101
G09G003/36 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 2005 |
JP |
2005-105980 |
Claims
1. A portable information terminal device comprising a display
device capable of switching between a wide viewing field mode in
which a display area is made to be browsed in a wide viewing angle
state and a narrow viewing field mode in which said display area is
made to be browsed in a narrow viewing angle state, wherein a
pattern area is formed in the display area of said display device;
in the wide viewing field mode, the whole of the display area is
brought into the wide viewing angle state; and in the narrow
viewing field mode, the display area except said pattern area is
brought into the narrow viewing angle state.
2. The portable information terminal device according to claim 1,
wherein a first pattern area and a second pattern area are formed
in said display area; in the wide viewing field mode, the whole of
the display area is brought into the wide viewing angle state; and
in the narrow viewing field mode, a first divided state in which
the display area except the first pattern area is brought into the
narrow viewing angle state, and a second divided state in which the
display area except the second pattern area is brought into the
narrow viewing angle state are dynamically switched.
3. A portable information terminal device comprising: a display
device for displaying information in a display area on a display
screen; and a viewing field switching device for switching a
viewing angle of said display screen, wherein: said viewing field
switching device comprises: a viewing field switching panel that is
arranged on said display screen and formed with a display
transmitting face having a predetermined pattern area in said
display area; viewing angle controlling means of controlling a
viewing angle of a background area that is the display area except
said pattern area; and mode switching means of switching between a
wide viewing field mode in which said display area is made to be
browsed in a wide viewing angle state and a narrow viewing field
mode in which said display area is made to be browsed in a narrow
viewing angle state; and said portable information terminal device
makes a viewing angle of said pattern area and that of said
background area coincide with each other in the wide viewing field
mode, and differentiates the viewing angles of said pattern area
and said background area from each other in the narrow viewing
field mode.
4. The portable information terminal device according to claim 3,
wherein said viewing angle controlling means can independently
control the viewing angles of said pattern area and said background
area.
5. The portable information terminal device according to claim 4,
wherein: said viewing field switching panel comprises: two
insulating transparent substrates arranged so as to face to each
other; a liquid crystal encapsulated between these insulating
transparent substrates; and two sheets of transparent electrodes
respectively formed on inner faces of said insulating transparent
substrates, at least one of said transparent electrodes is divided
into an electrode piece formed in said pattern area and that formed
in said background area; and said viewing angle controlling means
makes potentials of said electrode pieces coincide with each other
in the wide viewing field mode, and differentiates the potentials
of said electrode pieces from each other in the narrow viewing
field mode.
6. The portable information terminal device according to claim 3,
wherein: said display area is in a rectangular shape; and said
pattern area is in a shape extending in an oblique direction with
respect to said display area.
7. A portable information terminal device comprising: a display
device for displaying information in a display area on a display
screen; and a viewing field switching device for switching a
viewing angle of said display screen, wherein: said viewing field
switching device comprises: a viewing field switching panel that is
arranged on said display screen and formed with a display
transmitting face having a first pattern area and a second pattern
area in said display area; viewing angle controlling means of
controlling viewing angles of the first pattern area, the second
pattern area, and a background area that is the display area except
these pattern areas; and mode switching means of switching between
a wide viewing field mode in which said display area is made to be
browsed in a wide viewing angle state and a narrow viewing field
mode in which said display area is made to be browsed in a narrow
viewing angle state; and said portable information terminal device
makes the viewing angles of the first pattern area, the second
pattern area, and the background area coincide with one another in
the wide viewing field mode, and in the narrow viewing field mode,
dynamically switches between a first divided state in which the
viewing angle of the first pattern area is differentiated from
those of the remaining areas and a second divided state in which
the viewing angle of the second pattern area is differentiated from
those of the remaining areas.
8. The portable information terminal device according to claim 7,
wherein said viewing angle controlling means switches between said
first divided state and said second divided state at predetermined
time intervals.
9. The portable information terminal device according to claim 7,
wherein: said viewing field switching panel comprises: two
insulating transparent substrates arranged so as to face to each
other; a liquid crystal encapsulated between these insulating
transparent substrates; and two sheets of transparent electrodes
respectively formed on inner faces of said insulating transparent
substrates; the first pattern area, the second pattern area, and
the background area are formed by dividing at least one of said
transparent electrodes into two or more electrode pieces; and said
viewing angle controlling means makes potentials of said electrode
pieces coincide with each other in the wide viewing field mode, and
differentiates the potentials of said electrode pieces from each
other in the narrow viewing field mode.
10. A display terminal device comprising a display device capable
of switching between a wide viewing field mode in which a display
area is made to be browsed in a wide viewing angle state and a
narrow viewing field mode in which said display area is made to be
browsed in a narrow viewing angle state, wherein a pattern area is
formed in the display area of said display device; in the wide
viewing field mode, the whole of the display area is brought into
the wide viewing angle state; and in the narrow viewing field mode,
the display area except said pattern area is brought into the
narrow viewing angle state.
11. The display terminal device according to claim 10, wherein: a
first pattern area and a second pattern area are formed in said
display area; and in the wide viewing field mode, the whole of the
display area is brought into the wide viewing angle state; and in
the narrow viewing field mode, a first divided state in which the
display area except the first pattern area is brought into the
narrow viewing angle state, and a second divided state in which the
display area except the second pattern area is brought into the
narrow viewing angle state are dynamically switched.
Description
TECHNICAL FIELD
[0001] The present invention relates to a portable information
terminal device and a display terminal device, and more
particularly to a display terminal device capable of variably
controlling a view angle of a display device on which various types
of information are displayed, and thereby suppressing a peep of a
display screen, and to a portable information terminal device
having such a display device, such as a mobile telephone.
BACKGROUND ART
[0002] A small portable information terminal device can be carried
while being held in a pocket or bag, and is used in various places.
It is often used, for example, in a meeting room, restaurant,
train, or bus, on a station platform, or in other place. In such a
case, there exists a problem that other people around may peep at a
display screen of the portable information terminal device, and
therefore user's privacy may not be secured.
[0003] As measures for such peep, it can be considered that a
viewing angle of a display device is narrowed. For example, there
has been known a narrow viewing field film that can be attached to
a display screen of a mobile telephone. The narrow viewing field
film is a film that is transparent as viewed from the front, but
opaque (e.g. black) as viewed from an oblique direction, and has
some effect of preventing the peep. However, if this type of narrow
viewing field film is attached, image quality is deteriorated even
as viewed from the front, and therefore a user has to always view
such a low quality screen display. Also, as in the case where a
display screen is viewed by multiple people, usages such as viewing
the display screen from an oblique direction becomes
impossible.
[0004] Also, a technology for variably controlling the viewing
angle of the display device has been proposed (e.g., Patent
documents 1 and 2). Patent documents 1 describe configurations in
which a liquid crystal panel is used to control a viewing angle in
a display device of a mobile telephone, and Patent documents 2
describe configurations in which a liquid crystal panel is used to
control a viewing angle in a display device of a car navigation
system, respectively. In particular, in the car navigation system
of Patent document 2, a configuration in which the viewing angle of
a part of a display area is narrowed to thereby hide the partial
area from a driver's side is described.
[0005] Patent document 1: Japanese Unexamined Patent Publication
No.
[0006] Patent document 2: Japanese Unexamined Patent Publication
No.
DISCLOSURE OF THE INVENTION
Problem to be Solved by the Invention
[0007] In a conventional display device, by narrowing the viewing
angle of the display screen, the screen display is made difficult
to view from an oblique direction. However, even in such a display
device, it is impossible to completely hide the screen display from
the oblique direction, and the screen display just becomes
difficult to view due to a reduction in contrast even as viewed
from outside of the viewing angle. Accordingly, there exists a
problem that other people can peep at the display screen if
carefully viewing it even from the oblique direction.
[0008] The present invention is made in consideration of the above
circumstances, and therefore has an object to provide a display
terminal device capable of effectively suppressing a peep of the
display screen from the oblique direction. Also, it is another
object of the present invention to provide a portable information
terminal device capable of effectively suppressing a peep of the
display screen from the oblique direction.
[0009] The portable information terminal device and display
terminal device according to the present invention are capable of
switching a display device between a wide viewing field mode and a
narrow viewing field mode, and in the narrow viewing field mode, by
combining areas having a narrow viewing angle area and a wide
viewing angle area in a display area to attract the conscious of a
person attempting to peep from the oblique direction at to a
pattern arising from the difference in viewing angle in the display
area, prevent the peep.
[0010] A portable information terminal device of a first aspect of
the present invention is configured to include a display device
capable of switching between a wide viewing field mode in which a
display area is made to be browsed in a wide viewing angle state
and a narrow viewing field mode in which the display area is made
to be browsed in a narrow viewing angle state, wherein a pattern
area is formed in the display area of the display device; in the
wide viewing field mode, the whole of the display area is brought
into the wide viewing angle state; and in the narrow viewing field
mode, the display area except the pattern area is brought into the
narrow viewing angle state.
[0011] Such a configuration allow a high contrast pattern to be
visible based on the difference in viewing angle between the
pattern and background areas if a display screen is viewed from an
oblique direction in the narrow viewing field mode. That is, the
higher contrast pattern overlapped on a reduced contrast screen
display is visible. Accordingly, in the narrow viewing field mode,
the conscious of a person attempting to peep at the display screen
can be attracted to the high contrast pattern to thereby prevent
the low contrast screen display from being easily made out.
[0012] A portable information terminal device of a second aspect of
the present invention is configured such that in addition to the
above configuration, a first pattern area and a second pattern area
are formed in the display area; in the wide viewing field mode, the
whole of the display area is brought into the wide viewing angle
state; and in the narrow viewing field mode, a first divided state
in which the display area except the first pattern area is brought
into the narrow viewing angle state, and a second divided state in
which the display area except the second pattern area is brought
into the narrow viewing angle state are dynamically switched.
[0013] Such a configuration allows the high contrast pattern
visible from the oblique direction in the narrow viewing field mode
to be dynamically varied. For this reason, the conscious of the
person attempting to peep at the display screen can be attracted to
the moving pattern to thereby prevent the screen display from being
easily made out. Also, by varying the pattern areas, the screen
display in the pattern areas can be prevented from being easily
made out.
[0014] A portable information terminal device of a third aspect of
the present invention is one including: a display device for
displaying information in a display area on a display screen; and a
viewing field switching device for switching a viewing angle of the
display screen. The viewing field switching device includes: a
viewing field switching panel that is arranged on the display
screen and formed with a display transmitting face having a
predetermined pattern area in the display area; viewing angle
controlling means of controlling a viewing angle of a background
area that is the display area except the pattern area; and mode
switching means of switching between a wide viewing field mode in
which the display area is made to be browsed in a wide viewing
angle state and a narrow viewing field mode in which the display
area is made to be browsed in a narrow viewing angle state. Also,
the viewing field switching device makes a viewing angle of the
pattern area and that of the background area coincide with each
other in the wide viewing field mode, and differentiates the
viewing angles of the pattern area and the background area from
each other in the narrow viewing field mode.
[0015] A portable information terminal device of a fourth aspect of
the present invention is configured such that in addition to the
above configuration, the viewing angle controlling means can
independently control the viewing angles of the pattern area and
the background area.
[0016] A portable information terminal device of a fifth aspect of
the present invention is configured such that in addition to the
above configuration, the viewing field switching panel includes:
two insulating transparent substrates arranged so as to face to
each other; a liquid crystal encapsulated between these insulating
transparent substrates; and two sheets of transparent electrodes
respectively formed on inner faces of the insulating transparent
substrates, at least one of the transparent electrodes is divided
into an electrode piece formed in the pattern area and that formed
in the background area, and the viewing angle controlling means
makes potentials of the electrode pieces coincide with each other
in the wide viewing field mode, and differentiates the potentials
of the electrode pieces from each other in the narrow viewing field
mode. Such a configuration allows the viewing angles of the pattern
and background areas to be independently controlled within the
display transmitting face of the viewing field switching panel
configured by encapsulating the liquid crystal between the
electrodes.
[0017] A portable information terminal device of sixth aspect of
the present invention is configured such that in addition to the
above configuration, the display area is in a rectangular shape,
and the pattern area is in a shape extending in an oblique
direction with respect to the display area. Because of such a
configuration, a series of characters arranged in a horizontal or
vertical direction, a graphic extending in the horizontal or
vertical direction, and the like can be prevented from being easily
made out through the pattern area.
[0018] A portable information terminal device of a seventh aspect
of the present invention is configured to include: a display device
for displaying information in a display area on a display screen;
and a viewing field switching device for switching a viewing angle
of the display screen, wherein the viewing field switching device
includes: a viewing field switching panel that is arranged on the
display screen and formed with a display transmitting face having a
first pattern area and a second pattern area in the display area;
viewing angle controlling means of controlling viewing angles of
the first pattern area, the second pattern area, and a background
area that is the display area except these pattern areas; and mode
switching means of switching between a wide viewing field mode in
which the display area is made to be browsed in a wide viewing
angle state and a narrow viewing field mode in which the display
area is made to be browsed in a narrow viewing angle state, makes
the viewing angles of the first pattern area, the second pattern
area, and the background area coincide with one another in the wide
viewing field mode, and in the narrow viewing field mode,
dynamically switches between a first divided state in which the
viewing angle of the first pattern area is differentiated from
those of the remaining areas and a second divided state in which
the viewing angle of the second pattern area is differentiated from
those of the remaining areas.
[0019] A portable information terminal device of an eighth aspect
of the present invention is configured such that in addition to the
above configuration, the viewing angle controlling means switches
between the first divided state and the second divided state at
predetermined time intervals.
[0020] A portable information terminal device of a ninth aspect of
the present invention is configured such that in addition to the
above configuration, the viewing field switching panel includes:
two insulating transparent substrates arranged so as to face to
each other; a liquid crystal encapsulated between these insulating
transparent substrates; and two sheets of transparent electrodes
respectively formed on inner faces of the insulating transparent
substrates, the first pattern area, the second pattern area, and
the background area are formed by dividing at least one of the
transparent electrodes into two or more electrode pieces, and the
viewing angle controlling means makes potentials of the electrode
pieces coincide with each other in the wide viewing field mode, and
differentiates the potentials of the electrode pieces from each
other in the narrow viewing field mode. Such a configuration allows
the viewing angles of the first pattern, second pattern, and
background areas to be independently controlled within the display
transmitting face of the viewing field switching panel configured
by encapsulating the liquid crystal between the electrodes.
EFFECT OF THE INVENTION
[0021] The portable information terminal device of the present
invention is provided with the pattern areas having different
viewing angles in the display area in the narrow viewing field mode
in which the display area is made to be browsed in the narrow
viewing angle state. For this reason, if the display area is viewed
from the oblique direction in the narrow viewing field mode, the
pattern arising from the difference in viewing angle appears, and
thereby the conscious of the peeper can be attracted to the
pattern. Accordingly, the screen display can be prevented from
being easily made out or recognized from the oblique direction.
[0022] Also, in the narrow viewing field mode, by dynamically
switching between the different pattern areas in the display area,
a moving pattern appears if the display area is viewed from the
oblique direction, and thereby the conscious of the peeper can be
attracted to the pattern. Accordingly the screen display can be
further prevented from being easily made out or recognized from the
oblique direction.
BEST MODE FOR CARRYING OUT THE INVENTION
[0023] FIG. 1 is an external view illustrating an example of a
portable information terminal device according to an embodiment of
the present invention, in which a mobile telephone 1 is illustrated
as the example of the portable information terminal device. The
mobile telephone 1 is a so-called folding mobile telephone in which
a display case 100 and an operation case 200 are connected to each
other via a hinge part 300, and can be folded such that one face of
the display case 100 and that of the operation case 200 face to
each other.
[0024] The display case 100 has a main display part 101 and a
telephone receiver 103 arranged on a face thereof that becomes an
inner side when the mobile telephone 1 is folded, and a sub display
part 102 and a camera 104 arranged on the other face thereof that
becomes an outer side. Also, the operation case 200 has a plurality
of operation keys 201 and a telephone microphone 203 arranged on a
face thereof that becomes an inner side when the mobile telephone 1
is folded. Such a folding mobile telephone 1 can be carried in a
compactly folded state, and if the both cases 100 and 200 are
expanded, the operation keys 201 can be pressed down for operation
while display on the main display part 101 is viewed. That is, main
information is displayed with use of the main display part 101, and
main input operations are performed using the operation keys
201.
[0025] The main display part 101 includes the display area
typically having a portrait-oriented rectangular shape, on which
various types of information including personal information are
displayed. To prevent such display from being peeped by other
people, the main display part 101 can variably control a viewing
angle in a horizontal direction. In the present embodiment, the
viewing field modes can be switched between a wide viewing field
mode that is an operating state with a wider viewing angle and a
narrow viewing field mode that is an operating state with a
narrower viewing angle. The main display part 101 of the mobile
telephone typically has the display area smaller than those of a TV
receiver and stationary information terminal device, and is also
appropriate for the viewing angle control because the mobile
telephone is used in a user's hand and therefore a positional
relationship between eyes of the user and the display screen is
approximately constant. Further, the mobile telephone is used in a
state where the main display part 101 is made vertical to some
extent, so that by narrowing the viewing angle in the horizontal
direction, the peep can be effectively prevented.
[0026] The operation keys 201 include a viewing field switching
button 202 with which the user instructs to switch the viewing
angle of the main display part 101. In the wide viewing field mode
in which the main display part 101 is well visible from an oblique
direction, if the user operates the viewing field switching button
202, the main display part 101 is brought into the narrow viewing
field mode in which the main display part 101 is not easily visible
from the oblique direction. Subsequently, if the user operates the
viewing field switching button 202 again, the main display part 101
returns into the wide viewing field mode.
[0027] In the present embodiment, a case where the viewing angle
control is performed on the main display part 101 is described as
an example; however, it should be appreciated that a similar
viewing angle control can also be applied to the sub display part
102. Further, in the present embodiment, a case where the viewing
angle in the horizontal direction is controlled is described as an
example; however, the viewing angle in a vertical direction can
also be controlled in a similar manner.
[0028] FIG. 2 is an explanatory diagram illustrating examples of
how an image on the main display part 101 can be viewed in the
narrow viewing field mode. FIG. 2 (a) illustrate an image for a
case where the main display part 101 is viewed from a viewpoint
within the viewing angle in the narrow viewing field mode, and FIG.
2 (b) illustrates an image for a case where it is viewed from a
viewpoint outside the viewing angle in the narrow viewing field
mode.
[0029] In the wide viewing field mode, if the main display part 101
is viewed from a viewpoint within the viewing angle in the wide
viewing field mode, the screen display is of course well visible.
Similarly, in the narrow viewing field mode, if the main display
part 101 is viewed from the viewpoint within the viewing angle in
the narrow viewing field mode, the screen display is also well
visible as illustrated in FIG. 2 (a). In addition, in the narrow
viewing field mode, color quality and the like are slightly reduced
as compared with the wide viewing field mode; however, the screen
display is still well visible in general.
[0030] On the other hand, if the main display part 101 in the
narrow viewing field mode is viewed from a viewpoint that is within
the viewing angle in the wide viewing field mode but outside the
viewing angle in the narrow viewing field mode, the original screen
display is visible only with a low contrast as illustrated in FIG.
2 (b), and instead, a pattern substantially consisting of a
plurality of stars overlapped on the original screen display is
visible with a high contrast. This pattern can be provided by
partially differentiating the viewing angle in the display area of
the main display part 101.
[0031] On the main display part 101 in the narrow viewing field
mode, while the star pattern area is maintained in a wide viewing
angle state, the remaining background area is only brought into a
narrow viewing angle state. For this reason, if the main display
part 101 is viewed from the oblique direction, the pattern area
remains bright, and only the background area becomes dark, i.e.,
the high contrast pattern can be viewed as if it floats on the low
contrast display area.
[0032] Human vision is characterized by being unconsciously
attracted to the high contrast pattern, and not easily recognizing
the low contrast pattern if such a screen display on which the two
patterns having different contrasts are overlapped is viewed. The
mobile telephone 1 in the present embodiment prevents content of
the original screen display from being easily recognized or made
out by attracting the conscious of a peeper in this manner even if
the original screen display is visible with a low contrast.
[0033] In addition, if an inside of the pattern area is only
focused on, the screen display is easily visible as compared with a
case where the entire display area is brought into the narrow
viewing field state. However, if a shape of the pattern area is
devised by making a width or height thereof shorter, extending it
in the oblique direction, or taking other measures, the content can
be prevented from being easily recognized or made out in
combination with the above attracting action of the vision.
[0034] FIG. 3 is a cross-sectional view illustrating a
configuration example of the main display part 101, in which a
cross section along the line A-A in FIG. 1 is illustrated. The main
display part 101 is a display device substantially including a
viewing field switching panel 2 and a liquid crystal display module
5. On a display screen of the liquid crystal display module 5, a
display transmitting face of the viewing field switching panel 2 is
arranged, and if the viewing field switching panel 2 switches a
viewing angle of the display transmitting face, the viewing angle
of the main display part 101 can be switched.
[0035] The liquid crystal display module 5 is a well-known display
device substantially including a liquid crystal panel for display 3
and a backlight 4. The liquid crystal panel for display 3 has a
liquid crystal 34 encapsulated between two insulating transparent
substrates (e.g., glass substrates) 32a and 32b. Also, deflection
plates 31a and 31b are arranged on outer faces of the substrates
32a and 32b, respectively, and on inner faces of them, transparent
electrodes (e.g., ITO electrodes) 33a and 33b are respectively
formed. For example, in a case of a general TFT liquid crystal
panel for display, a common electrode is formed as the electrode
33a on a front side, and a plurality of pixel electrodes are formed
as the electrode 33b on a rear side.
[0036] The backlight 4 is a light source supplying light to the
transmissive liquid crystal panel for display 3 from the rear side.
The liquid crystal panel for display 3 controls whether or not
incident light from the backlight 4 is transmitted on a
pixel-by-pixel basis by controlling potential of each of the pixel
electrodes, to display characters and images. That is, an area on
the substrate 32b arranged thereon with the above pixel electrodes
corresponds to the display area, and by differentiating a
transmittance for the light depending on a position in the display
area, information including characters, graphics, and the like is
displayed.
[0037] On the other hand, the viewing field switching panel 2
provides variable control of the viewing angle by differentiating
the light transmittance depending on a traveling direction of the
light. In addition, an area through which the light from the liquid
crystal display module 5 is transmitted, i.e., an area on the
viewing field switching panel 2 corresponding to the display area
of the liquid crystal display module 5 is referred to as the
display transmitting face.
[0038] The viewing field switching panel 2 has a liquid crystal 24
encapsulated between two insulating transparent substrates 22a and
22b (e.g., glass substrates), and on an outer face of the substrate
22a on the front side, a deflection plate 21 is arranged, whereas
on inner faces of the substrates 22a and 22b, transparent
electrodes 23a and 23b (e.g., ITO electrodes) are respectively
formed. That is, if the deflection plate 31a of the liquid crystal
panel for display 3 is added, a configuration of the viewing field
switching panel 2 becomes the same as that of the liquid crystal
panel for display 3.
[0039] The deflection plates 21 and 31a are arranged such that
transmission axes of them coincide with each other, and the
incident light from the liquid crystal panel for display 3 can be
transmitted through the viewing field switching panel 2 unless a
deflection surface fluctuates in the liquid crystal 24. In the
liquid crystal 24, because the deflection surface of transmitting
light rotates depending on an angle formed by a light axis of the
transmitting light with the front direction, the incident light
obliquely traveling in the liquid crystal 24 toward outside of a
predetermined viewing angle is blocked by the deflection plate
21.
[0040] FIGS. 4 and 5 are diagrams for describing a principle of the
viewing angle control, and FIG. 4 is a schematic diagram
illustrating an appearance in the wide viewing field mode, of which
(a) is a perspective view, and (b) is a view in the direction of an
arrow C. Also, FIG. 5 is a schematic diagram illustrating an
appearance in the narrow viewing field mode, of which (a) is a
perspective view, and (b) is a view in the direction of an arrow
D.
[0041] The main display part 101 varies the viewing angle of the
display screen in the horizontal direction by making both of the
transmission axes a1 and a2 of the deflection plates 21 and 31a
coincide with the vertical direction of the display screen to
control orientation directions of liquid crystal molecules 24e
(molecules of the liquid crystal 24) arranged between the
deflection plates 21 and 31a.
[0042] In the wide viewing field mode, the liquid crystal molecules
24e are oriented so as to be parallel to the transmission axes a1
and a2 (see FIG. 4). At this time, even if the viewing field
switching panel 2 is viewed from a viewpoint e1 on the front side,
or alternatively even if it is viewed from a viewpoint e2 of which
a direction forms a horizontal angle .alpha. with that of the
viewpoint e1, the orientation directions of the liquid crystal
molecules 24e seem to coincide with the transmission axes a1 and
a2. Accordingly, regardless of a light traveling direction, the
incident light from the liquid crystal panel for display 3 can be
transmitted through the deflection plate 21 without being subjected
to birefringence in the liquid crystal 24. The viewing angle of the
main display part 101 is maximized in this case, and coincides with
the viewing angle of the liquid crystal panel for display 3.
[0043] On the other hand, in the narrow viewing field mode, an
electric field is formed between the electrodes 23a and 23b to
thereby rotate the liquid crystal molecules 24e from a state
illustrated in FIG. 4 and orient them so as to form an angle
.theta. with the transmission axes a1 and a2 (see FIG. 5). However,
the liquid crystal molecules 24e are only tilted in an
anteroposterior direction by the above rotation, and a projection
image on the display screen is still maintained parallel to the
transmission axes a1 and a2. That is, the liquid crystal molecules
24e are rotated in a plane that is perpendicular to the display
screen and parallel to the transmission axes a1 and s2.
[0044] If the viewing field switching panel 2 in such a narrow
viewing field mode is viewed from the viewpoint e1 on the front
side, the orientation directions of the liquid crystal molecules 24
seem to coincide with the transmission axes a1 and a2, similarly to
the case of the wide viewing field mode; however, if viewed from
the viewpoint e2 of which the direction forms the horizontal angle
.alpha. with that of the viewpoint e1, the orientation directions
of the liquid crystal molecules 24e seem to form an angle .beta.
with the transmission axes a1 and a2. For this reason, light
traveling toward the viewpoint e2 has the deflection surface
rotated in the liquid crystal 24 depending on the angle .beta., and
is therefore attenuated or blocked at the deflection plate 21. The
angle .beta. is varied depending on the angles .theta. and .alpha.,
so that the viewing angle depending on the angle .theta. is
obtained.
[0045] Accordingly, the viewing angle of the viewing field
switching panel 2 can be linearly varied depending on the angle
.theta. formed by the orientation directions of the liquid crystal
molecules 24e with the transmission axes a1 and a2. However, it
should be noted that in the present embodiment, the viewing field
modes are controlled by switching between the wide viewing field
mode in which the electrodes 23a and 23b are brought into the same
potential state and the narrow viewing field mode in which they are
brought into different potential states.
[0046] FIG. 6 is a diagram illustrating a configuration example of
the electrodes 23a and 23b of the viewing field switching panel 2
illustrated in FIG. 2. Each of the electrodes 23a and 23b is
divided into one or more pattern areas and a background area
excluding the pattern areas, and each of the areas is configured as
an independent electrode piece. The electrode piece is provided
with a narrow gap (e.g., 12 .mu.m at minimum) with a neighboring
electrode piece, and thereby both of the electrode pieces are
electrically insulated from each other.
[0047] The electrode 23a on the front side is formed with three
types of character patterns "SHARP", "DoCoMo", and "FOMA" (any of
these patterns is a trademark or registered trademark). These
character patterns and the remaining background are respectively
formed as independent electrode pieces, and can be controlled to
different potentials. In the present embodiment, the background is
connected to an electrode terminal Ta0, "SHARP" to an electrode
terminal Ta1, "DoCoMo" to an electrode terminal Ta2, and "FOMA" to
an electrode terminal Ta3.
[0048] Also, the electrode 23b on the rear side is formed with a
pattern including a plurality of stars. This pattern is an
aggregate of small star-shaped pattern pieces, and any two
neighboring pattern pieces on an obliquely directed line from upper
right to lower left in the display area are connected to each
other, based on which a plurality of pattern lines extending in the
oblique direction are formed. These pattern lines are connected to
an electrode terminal Tb1 or Tb2 such that any two neighboring
pattern lines are respectively connected to the different electrode
terminals. That is, a first pattern in which a plurality of pattern
lines are combined in a comb shape and connected to the electrode
terminal Tb1, and a second pattern in which a plurality of pattern
lines are combined in a comb shape and connected to the electrode
terminal Tb2 are arranged in a state where teeth of one of the
combs are combined with those of the other one so as to be inserted
into gaps between the teeth of the other one. The first and second
patterns, and the remaining background are respectively formed as
independent electrode pieces, and the background is connected to an
electrode terminal Tb0.
[0049] If any of two different voltage levels (e.g., 0 V and 3 V)
is applied to the above-described electrode terminals Ta0 to Ta3,
and Tb0 to Tb2, an area between an opposed pair of electrode pieces
having different potentials is brought into the narrow viewing
angle state, and that between an opposed pair of electrode pieces
having the same potential is brought into the wide viewing angle
state. Accordingly, depending on a combination of the voltage
levels applied to the respective electrode terminals Ta0 to Ta3,
and Tb0 to Tb2, the viewing angle within the display area can be
partially differentiated.
[0050] FIGS. 7 and 8 are diagrams illustrating examples of the
display transmitting face of the viewing field switching panel 2 in
the narrow viewing field mode, in which examples of the pattern
area partially brought into the wide viewing angle state in the
narrow viewing field mode are illustrated.
[0051] FIGS. 7 (a) to (e) illustrate examples of the pattern area,
which are formed in the display area in the narrow viewing field
mode with use of the character patterns of the electrode 23a on the
front side based on the difference in viewing angle. In the present
embodiment, any of FIGS. 7 (a) to (e) is described on an assumption
that the electrode terminals Tb0 to Tb2 of the electrode 23b on the
rear side are applied with a high level voltage (3 V).
[0052] FIG. 7 (a) illustrates a case where the electrode terminal
Ta1 is applied with the high level voltage (3V), and those Ta0,
Ta2, and Ta3 with a low level voltage (0 V). In this case, the
character pattern area "SHARP" connected to the electrode terminal
Ta1 is not formed with an electric field, and therefore brought
into the wide viewing angle state, and the remaining area is formed
with an electric field, and therefore brought into the narrow
viewing angle state.
[0053] Similarly, FIG. 7 (b) illustrates a case where the electrode
terminal Ta2 is applied with the high level voltage, those Ta0,
Ta1, and Ta3 with the low level voltage, and the character pattern
area "DoCoMo" is only brought into the wide viewing angle state.
Also, FIG. 7 (c) illustrates a case where the electrode terminal
Ta3 is applied with a high level voltage, those Ta0 to Ta2 with a
low level voltage, and the character pattern area "FOMA" is only
brought into the wide viewing angle state.
[0054] Further FIG. 7 (d) illustrates a case where the electrode
terminals Ta1 and Ta2 are applied with the high level voltage,
those Ta0 and Ta3 with the low level voltage, and the two character
pattern areas "SHARP" and "DoCoMo" are simultaneously brought into
the wide viewing angle state. Still further, FIG. 7 (e) illustrates
a case where the electrode terminals Ta1 to Ta3 are applied with
the high level voltage, that Ta0 with the low level voltage, and
the three character pattern areas "SHARP", "DeoCoMo", and "FOMA"
are simultaneously brought into the wide viewing angle state.
[0055] FIGS. 8 (a) to (c) illustrate examples of the pattern area,
which are formed in the display area in the narrow viewing field
mode with use of the graphic pattern of the electrode 23b on the
rear side based on the difference in viewing angle. In the present
embodiment, any of (a) to (c) is described on an assumption that
the electrode terminals Ta0 to Ta3 of the electrode 23a on the
front side are applied with the high level voltage.
[0056] FIG. 8 (a) illustrates a case where the electrode terminal
Tb1 is applied with the high level voltage, and those Tb0 and Tb2
with the low level voltage. In this case, the first pattern area
connected to the electrode terminal Tb1 is brought into the wide
viewing angle state, and the remaining area into the narrow viewing
angle state. FIG. 8 (b) illustrates a case where the electrode
terminal Tb2 is applied with the high level voltage, those Tb0 and
Tb1 with the low level voltage, and the second pattern area
connected to the electrode terminal Tb2 is only brought into the
wide viewing angle state. FIG. 8 (c) illustrates a case where the
electrode terminals Tb1 and Tb2 are applied with the high level
voltage, that Tb0 with the low level voltage, and the first and
second pattern areas are simultaneously brought into the wide
viewing angle state.
[0057] FIG. 8 (d) illustrates a case where the pattern areas having
the wide viewing angle are formed with use of the both patterns of
the electrodes 23a and 23b. That is, a case is described where the
electrode terminals Ta1 and Tb2 are applied with the low level
voltage, those Ta0, Ta2, Ta3, Tb0, and Tb1 with the high level
voltage, and the "SHARP" and second pattern areas are
simultaneously brought into the wide viewing angle state.
[0058] As described above, based on the combination of the voltage
levels applied to the respective electrode pieces constituting the
electrodes 23a and 23b, an area to be partially brought into the
wide viewing angle state can be selected from various combinations
of the patterns in the narrow viewing field mode. Note that in FIG.
8 (d), an area in which the second pattern and the character
pattern "SHARP" are overlapped is not formed with an electric
field, and therefore brought into the narrow viewing angle state.
Accordingly, there is no chance that a local area having large
width and height is generated as a result of the combination of the
pattern area formed by the electrode piece 23a on the front side
and that formed by the electrode piece 23b on the rear side. Also,
as illustrated in FIGS. 6 to 8, each of the pattern areas is formed
so as to be smaller in dimensions than the background area.
[0059] FIG. 9 is a block diagram illustrating an example of an
internal configuration of the mobile telephone 1 illustrated in
FIG. 1. A main control unit 400 is a processor for controlling main
operations of the mobile telephone 1. In the present embodiment,
the main control unit 400 controls the telephone receiver 103, a
camera 104, operation keys 201, a telephone microphone 203, a
wireless unit 401, a viewing angle controller 402, and an LCD
controller 403.
[0060] The wireless unit 401 transmits/receives electromagnetic
waves to/from an unshown base station to exchange call sound or
electronic mails. The LCD controller 403 supplies drive signals to
the main display part 101 and the sub display part 102. The viewing
angle controller 402 supplies a drive signal to the viewing field
switching panel 2 to perform the switching control of the viewing
angle, and constitutes a viewing field switching device along with
the viewing field switching panel 2.
[0061] The main control unit 400 outputs a control signal to the
viewing angle controller 402 when the viewing field switching
button 202 is operated, or when any of the other operation keys 201
is operated to thereby change a setting of the viewing angle
control. The viewing angle controller 402 generates voltage signals
applied to the respective electrode terminals Ta0 to Ta3, and Tb0
to Tb2 of the viewing field switching panel 2, based on the control
signal.
[0062] FIG. 10 is a block diagram illustrating a configuration
example of the viewing angle controller 402 illustrated in FIG. 9.
The viewing angle controller 402 substantially includes a voltage
control unit 410, PWM generation circuit 411, inverter 412, seven
switching elements 413, and seven amplifiers 414.
[0063] The PWM generation circuit 411 generates a pulse signal for
AC driving of the viewing field switching panel 2. For example, a
pulse signal having a frequency of 70 Hz is generated. The inverter
412 generates an inverted signal into which the pulse signal
(non-inverted signal) is inverted. The seven switching elements 413
select and output either the non-inverted or inverted signal. The
output signal from each of the switching elements 413 is amplified
to a predetermined voltage level by a corresponding one of the
amplifiers 414, and then output to a corresponding one of the
electrode terminals Ta1 to Ta4, and Tb1 to Tb2
[0064] The voltage control unit 410 controls the seven switching
elements 413 to switch between the wide and narrow viewing field
modes or between the wide viewing angle patterns in the narrow
viewing field mode, based on an instruction of the main control
unit 400.
[0065] In the case of the AC driving of the viewing field switching
panel 2, if the opposed electrodes 23a and 23b are applied with
pulse signals having the same phase, the viewing field switching
panel 2 is brought into the wide viewing angle state, whereas if
they are applied with pulse signals having reverse phases, it is
brought into the narrow viewing angle state. For this reason, in
the wide viewing field mode, the voltage control unit 410 controls
the switching elements 413 so as to supply pulse signals having the
same phase (e.g., non-inverted signals) to all of the electrode
terminals Ta1 to Ta3, and Tb1 to Tb2. Also, to display the
character pattern "SHARP" having the wide viewing angle in the
narrow viewing field mode, it is only necessary to control the
switching elements 413 so as to supply the non-inverted signals to
the electrode terminals Ta0, Ta2, and Ta3, and the inverted signals
to the remaining electrode terminals Ta1, and Tb0 to Tb2,
[0066] FIG. 11 is a diagram illustrating an example for a case
where the pattern areas having the wide viewing angle are
dynamically switched in the narrow viewing field mode. Both of
FIGS. 11 (a) and (b) illustrate appearances of the main display
part 101 in the narrow viewing field mode as viewed from a
horizontally oblique direction; however, the pattern area brought
into the wide viewing angle state is different between FIGS. 11 (a)
and (b). By dynamically switching between the wide viewing angle
patterns illustrated in FIGS. 11 (a) and (b) in the narrow viewing
field mode, a moving pattern is visible by people peeping at from
the oblique direction.
[0067] Such dynamic switching between the patterns is performed by
the voltage control unit 410 illustrated in FIG. 10, in which the
wide viewing angle patterns illustrated in FIGS. 11 (a) and (b) are
alternately switched every time a predetermined time period
elapses. For example, the patterns are switched every one to two
seconds. In general, the human vision is characterized by being
attracted to a moving pattern, so that if the high contrast moving
pattern is overlapped on the low contrast display area, the
conscious of a peeper can be strongly attracted to the pattern, and
therefore the low contrast screen display can be further prevented
from being easily recognized or made out.
[0068] In addition, the dynamic switching of the wide viewing angle
pattern may not be necessarily performed at regular intervals;
however; it should be switched at a timing enough for human eyes to
recognize the pattern as being dynamic, and if the switching timing
is too early, a sufficient effect cannot be obtained. In the case
of the AC driving, the wide viewing angle pattern should be
switched at intervals at least longer than a cycle of the AC
driving, and is preferably switched at intervals, for example,
equal to or longer than 1/10 seconds.
[0069] Note that in the present embodiment, the case where the two
pattern areas are switched is described as an example; however, it
is more effective if three or more pattern areas different from one
another are sequentially switched. Also, it is further effective if
three or more wide viewing angle patterns different from one
another are switched while the switching sequence is varied.
[0070] FIG. 12 is a diagram illustrating an example of a procedure
for a user to set the viewing angle control, in which how a setting
screen displayed on the main display part 101 moves to another one
is illustrated. FIG. 12 (a) illustrates a viewing field switching
setting screen for the user to set the viewing field switching. On
the viewing field switching setting screen, the user can select a
silent mode interlock setting or pattern setting. The silent mode
interlock setting is an option for setting to interlock the narrow
viewing field mode with a silent mode, and the pattern setting is
an option for changing the wide viewing angle pattern in the narrow
viewing field mode. If the user selects the pattern setting and
then operates an enter key on the viewing field switching setting
screen, the screen moves to a pattern setting screen illustrated in
FIG. 12 (b).
[0071] The user can select any pattern from a plurality of prepared
patterns on the pattern setting screen. Options "Pattern A",
"Pattern B", and "Pattern C" are intended for fixed pattern
settings without the dynamic switching, and an option "Continuous
pattern switching" is intended for a setting for dynamically
switching between two or more patterns. By selecting any of the
options and operating the enter key, a message indicating that a
pattern setting has been complete, as illustrated in FIG. 12 (c),
is popped up, and then the screen returns to the viewing field
switching setting screen illustrated in FIG. 12 (a).
[0072] On the other hand, if the user operates a check key while
the pattern setting screen illustrated in (b) is displayed, a
pattern checking screen illustrated in (d) including a message
prompting to check a pattern is displayed. While the pattern
checking screen is displayed, the screen is in the narrow viewing
angle mode, and therefore the user can check a selected wide
viewing angle pattern. Also, by operating the check key or a clear
key while the pattern checking screen is displayed, the screen
moves to the screen illustrated in (c), or returns to the pattern
setting screen illustrated in (b).
[0073] Steps S101 to S106 in FIG. 13 represent a flowchart
illustrating an example of narrow viewing field mode processing.
The narrow viewing field mode processing represents an operating
procedure for the viewing angle controller 402 in the narrow
viewing field mode, and is started if the user operates the viewing
field switching button 202 in the wide viewing field mode.
[0074] First, the viewing angle of the display area is narrowed
based on a user setting on the pattern setting screen illustrated
in FIG. 12 (step S101). In the wide viewing field mode, the entire
display area is in the wide viewing angle state, so that the
viewing angle of the display area is narrowed except a pattern area
specified by the user. In addition, if the "Ccontinuous pattern
switching" is selected on the pattern setting screen, dynamically
switchable arbitrary patterns are used, and a timer is started.
[0075] If the user selects not any of the fixed patterns but the
"Continuous pattern switching", and the above timer has been time
up because a predetermined time period has elapsed, the pattern
area is switched to another one (steps S102 to S104). At this time,
the above timer is restarted.
[0076] The above steps S102 to S104 are repeated until the narrow
viewing field mode is terminated (step S105). To move to the wide
viewing field mode after the user operates the viewing field
switching button 202 to terminate the narrow viewing field mode,
the entire display area is brought into the wide viewing angle
state, and the narrow viewing field mode processing is terminated
(step S106).
[0077] Note that in the present embodiment, the mobile telephone is
described as an example; however, the scope of the present
invention is not limited to the mobile telephone. In general, the
portable information terminal device such as the mobile telephone
is preferred for the present invention because it is often used out
of doors where the device is likely to be peeped by other people
around; however, the scope of the present invention is not limited
to such a portable terminal device. That is, any terminal device
required to prevent the other people around from peeping at can be
applied with the present invention, regardless of whether the
terminal device is portable or stationary. For example, a financial
terminal device such as an automatic teller machine for depositing
cash and withdrawing cash, and for lending out money and repaying
which displays personal information in an environment where there
are other people around, can also be applied with the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0078] FIG. 1 is an external view illustrating an example of a
portable information terminal device according to an embodiment of
the present invention, in which a mobile telephone 1 is illustrated
as the example of the portable information terminal device.
[0079] FIG. 2 is an explanatory diagram illustrating an example of
how an image on the main display part 101 can be viewed in the
narrow viewing field mode, (a) illustrates an image viewed from a
viewpoint within the viewing angle, and (b) an image viewed from a
viewpoint outside the viewing angle.
[0080] FIG. 3 is a cross-sectional view illustrating a
configuration example of the main display part 101, in which a
cross section along the line A-A in FIG. 1 is illustrated.
[0081] FIG. 4 is a schematic diagram for describing a principle of
the viewing angle control, in which a case of a wide viewing field
mode is illustrated.
[0082] FIG. 5 is a schematic diagram for describing the principle
of the viewing angle control, in which a case of a narrow viewing
field mode is illustrated.
[0083] FIG. 6 is a diagram illustrating a configuration example of
the electrodes 23a and 23b of the viewing field switching panel 2
illustrated in FIG. 2.
[0084] FIG. 7 is a diagram illustrating examples of a display
transmitting face of the viewing field switching panel 2 in the
narrow viewing field mode.
[0085] FIG. 8 is a diagram illustrating other examples of the
display transmitting face of the viewing field switching panel 2 in
the narrow viewing field mode.
[0086] FIG. 9 is a block diagram illustrating an example of an
internal configuration of the mobile telephone 1 illustrated in
FIG. 1.
[0087] FIG. 10 is a block diagram illustrating a configuration
example of the viewing angle controller 402 illustrated in FIG.
9.
[0088] FIG. 11 is a diagram illustrating an example for a case
where wide viewing angle patterns are dynamically switched in the
narrow viewing field mode.
[0089] FIG. 12 is a diagram illustrating an example of a procedure
for a user to set the viewing angle control, in which how a setting
screen moves to another one is illustrated.
[0090] FIG. 13 is a flowchart illustrating an example of narrow
viewing field mode processing.
DESCRIPTION OF REFERENCE SYMBOLS
[0091] 1: Portable information terminal device (mobile telephone)
[0092] 2: Viewing field switching panel [0093] 3: Liquid crystal
panel for display [0094] 4: Backlight [0095] 5: Liquid crystal
display module [0096] 21, 31a, 31b: Deflection plate [0097] 22a,
22b, 32a, 32b: Insulating transparent substrate [0098] 23a, 23b,
33a, 33b: Transparent electrode [0099] 24, 34: Liquid crystal
[0100] 101: Main display part [0101] 102: Sub display part [0102]
201: Operation key [0103] 202: Viewing field switching button
[0104] 400: Main control unit [0105] 402: Viewing angle controller
[0106] 403; LCD controller [0107] 410: Voltage control unit [0108]
411: PWM generation circuit [0109] 412: Inverter [0110] 413:
Switching element [0111] 414: Amplifier [0112] a1, a2: Transmission
axis [0113] e1, e2: Viewpoint [0114] Ta0 to Ta4: Electrode terminal
on front side [0115] Tb0 to Tb2: Electrode terminal on rear
side
* * * * *